The present invention relates generally to improvements in the mobilization of structures for transport and, more particularly, but not by way of limitation, to the mobilization of oil field storage tank batteries.
When an oil well is brought into production, it will generally produce salt water as well as the oil for which the well was drilled. As noted in my co-pending U.S. patent application entitled "Oil Well Fluid Processing System", it is common practice to separate the oil from the salt water, as well as from natural gas also produced by the well, for storage of the oil and salt water in separate tanks of a tank battery emplaced at the oil well site. The oil is sold from tanks of the battery and the salt water is temporarily stored so that it can subsequently be disposed of without harming the environment.
The storage of the oil and salt water has, in the past, entailed considerable expense. Initially, and with particular reference to the storage of oil, the tanks of the battery have been constructed in the form of cylinders to exploit the rigidity of a cylindrical structure against hydrostatic pressure by liquids it contains. With this rigidity, the volume of the oil in the tank is proportional to the depth of the oil in the tank so that the buyer of the oil can determine the quantity of oil he has purchased by measuring this change in depth and applying an appropriate conversion factor. The other side of the coin is that cylindrical tanks are expensive to construct because of the necessity of bending plate metal from which the tank is constructed into arcuate sections.
Additionally, the construction of tanks in the form of cylinders has resulted in high expenses in the transportation of the tanks to the well site and the emplacement of the tanks to form a tank battery. For transportation purposes, the width of a cylindrical tank is its diameter and the diameter is fixed by the height and volume of the tank. As a result, cylindrical tanks will often present a wide load to be transported. Similarly, cylindrical tanks cannot be packed together into a compact load because of the curvature of their surfaces. As a result, the tanks of storage tank batteries for oil fields have, in the past, been transported to oil fields as individual units which must be individually placed and connected among themselves and to the well prior to use. The interconnection of the tanks is a time consuming job because of the necessity of cutting pipe to lengths that depend upon the placement of the tanks and threading the ends of the pipes for screw connections necessary to prevent leakage. Thus, considerable expense has been associated with both the transportation and the emplacement of the cylindrical tanks that comprise conventional storage tank batteries.
Moreover, it will often occur that the well will not produce oil in sufficient quantity for the continuation of production from the well to be commercially feasible. When this occurs, not only is the initial cost of transporting the tank battery to the well and emplacing the battery for production lost but additional cost is incurred in dismantling the tank battery and transporting the tanks from the site of the well.